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Yes, the post-1910 ledgers use "dural" consistently, and I don't recall seeing "aluminium" or "Al" at all.

Actually, the references to Duralumin don't start until 1920 in the Wheatstone ledgers ...

Though, thinking about it, I'm sure that I once had a circa 1910 Æola treble with (highly unusual) aluminium shoes and a bright green leather bellows, but I think the serial number might have been below 25000 so it wouldn't be in the surviving ledgers.

Now who did I sell it to?

Edited to add:

Maybe it was # 25750, which I've just traced in the ledgers, though there's no reference to aluminium shoes.

I based my earlier 1920 assertion on the evidence of a post, by someone who had been working on the ledgers, in an earlier thread on the topic (it's been discussed a few times before!), and it's still correct as regards the use of the term "Dural". But my own hunt through them tonight has now turned up what appears to be a first Duralumin entry for # 26232, a 75-key Duet (described as Durlum) made for Percy Honri in January 1914. I thought I'd seen early photos of him with one, perhaps inspired by/in competition with Alexander Prince's aluminium Edeophone?

There's also a 72-key Crane duet (Durelanum), # 26413, and a [Maccann] Duet (Durum), # 26482, both in June 1914, and a 65-key Crane (Duro), # 26969, in December 1915. However, the next entry doesn't appear until the 64-key Special (Dural), # 28438, in June 1920, so it would seem likely that "the War Effort" had probably made Duralumin unobtainable in the meantime. From 1920 onwards they regularly used it.

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Maybe it was # 25750, which I've just traced in the ledgers, though there's no reference to aluminium shoes.

Hi Stephen,

I bought this one from Hobgoblin in 1992.

2nd December 1912 in the Wheatstone ledgers. As posted either earlier in this thread, or the other one on Aluminium reed frames, this has a combination of Aluminium and Brass reed frames. The largest 75% are Aluminium, leading to the greatest weight saving. The instument is in amazing condition; absolutely spotless inside.

Note also the non-standard dimension (6.25"), and I've not found another to this specification.

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Maybe it was # 25750, which I've just traced in the ledgers, though there's no reference to aluminium shoes.

Hi Stephen,

I bought this one from Hobgoblin in 1992.

2nd December 1912 in the Wheatstone ledgers. As posted either earlier in this thread, or the other one on Aluminium reed frames, this has a combination of Aluminium and Brass reed frames. The largest 75% are Aluminium, leading to the greatest weight saving. The instument is in amazing condition; absolutely spotless inside.

Thanks Peter, that must be the one then. My memory of it is that it was indeed in near-mint condition, though I'd forgotten that the high reeds were on brass plates (something you sometimes see in high quality accordions), but then it must be around 20 years since I last saw it.

A pretty unique Æola, and maybe the earliest one known with aluminium shoes? Could they even be Duralumin?

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Dural is very much harder. If you are familiar with both you can tell from the feel as you draw a pointed tool across the surface. Pure Al feels soft and smooth, Dural feels hard and scratchy. You probably need to have tried both to be able to recognise the difference though.

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My faith is restored by this article having recently read sales advertising blurb Condemning Wheatstones aluminium shoes and warning buyers to avoid them. As an owner of several 7a anglos I personally disliked these comments but I suppose we all are allowed our own opinions.

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As for me as a person who works with reeds i would prefer brass reeds in most cases if i look at it in the long run.

I don't hear a difference that i really can point down to the different frame material used. Especial on piccolo reeds brass is used and chromed, to give the same appearance as aluminium. The reason is because on the tiny reeds brass is better to work with to get the same precision.

On very low pitched and big Helicon reeds Aluminium is in most cases used but i also did tray brass and carbon. My test did not give any noticeable difference in sound if the same tongue and Box was used. But it is much harder to work with farms that are not as rigide as others. If frames are screwed to the chamber some tension is put on to the frame that may lead to tounges not vibrating freely as the should.

Corrosion on some aluminium alloy may be a problem. Usually in very old Boxes this can be the case but never with all, especially if the are not waxed. Brass reeds are in most cases in much better condition in very old boxes as other frame materials. For me the sound my be affected to a very little amount but i would not be able to tell how and how much. This differences i notice my be well caused by other differences in reed sets as well. Every set is a little bit diffident even if it is totally comparable. For sure is, that brass reed sets sound in average nearly or totally the same as comparable sets with Aluminium frames. If you don't mind more mass for a Box and the added price difference go with brass reeds you want regret it. In the long ran the reeds may be looking as new after 100 Years only changed in color. If the tounges also stays without rust then you are lucky. In most cases we all will be well of also with aluminum reeds lasting a human lifetime as well. Yes and a combination of aluminium for low pitched reeds and brass for higher pitched reeds would also be a nice choice and no problem to mix. Especial for reeds sounding higher as 800 Hz. Brass would be preferable to work with. Best regards, Johann

Edited November 1, 2017 by Johann

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I have been wondering whether there is any particular benefit, for concertina reeds, to using a high strength aluminium-copper alloy (colloquially known as Duralumin or Dural) rather than a much more commonly-available alloy like 6061-T6 (colloquially known as "aircraft grade aluminium"). I have read that aluminium-copper alloys are particularly prone to corrosion: you can buy it with a pure aluminium plating ("alclad"), but that only protects the unmachined top surface of the reed, not the vent sides or outer edge.

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6061-T6 is heat tempered and I suspect that machining it would remove the temper.

If this is true then, given the size of a concertina reed, making a small tempering oven and quenching bath should not be too difficult.

A bit easier than tempering a lamp pole or a sailboat mast...

I believe both 6061 and 6063 are precipitation hardened by holding them at around 300 degrees F for a few hours depending on thickness. It is not quenched after heating. T6 means that it has already been hardened either by heat treating or cold working as opposed to annealled stock. Hardened here is a relative term, only comparing it to the soft state, not to other metals like tool steel or any steel for that matter. Machining does not affect the hardened state unless it is heated much hotter and rapidly cooled. ( this has the opposite effect to quenching hardenable steel alloys ). I have successfully used my home oven for the work when making my bellows mold bars. Starting with T6 stock, you can ship any further hardening.

Dana

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My experience with 6061-T6 is in the context of welding together pieces of aluminium pipe to make sailboat masts. I was told that welding completely removes all temper from the aluminum and that a complete high temp bake and quench is needed to bring the metal back up to T4 temper and then precipitation hardening to T6, see:

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6061-T6 is heat tempered and I suspect that machining it would remove the temper.

If this is true then, given the size of a concertina reed, making a small tempering oven and quenching bath should not be too difficult.

A bit easier than tempering a lamp pole or a sailboat mast...

I believe both 6061 and 6063 are precipitation hardened by holding them at around 300 degrees F for a few hours depending on thickness. It is not quenched after heating. T6 means that it has already been hardened either by heat treating or cold working as opposed to annealled stock. Hardened here is a relative term, only comparing it to the soft state, not to other metals like tool steel or any steel for that matter. Machining does not affect the hardened state unless it is heated much hotter and rapidly cooled. ( this has the opposite effect to quenching hardenable steel alloys ). I have successfully used my home oven for the work when making my bellows mold bars. Starting with T6 stock, you can ship any further hardening.Dana

Would it really be necessary to harden or use the pre hardened 6061 though? I mean its not like those frames are going to be exposed to much stress/abrasion in their lifetime right?

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As I see it the main problem with OLD Aluminium reed shoes is that old Ally had a Magnesium additive( see Metals in the Service of Man ) This caused it to degrade very rapidly We use a Tooling grade Ally , about 3 000 kg per annum and get fantastic mould life from it. For example a Sanding Block mould we designed and made 30 years ago is still in production and has made over 500,000 parts

So if modern Ally is used there is no need to worry, but Gawd help you if you buy a Tina with Magnesium Alloy Ally shoes

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Given all of the above, it would seem like a good idea to use 6061-T6 aluminium instead of steel for reed shoes. The Al is about 1/3rd the weight of steel and the reed shoes constititute most of the weight of a concertina. That would be a big win.

FWIW One problem I have encountered with 6061-T6 is when you screw directly into tapped holes in the metal. Over time, the inside of the tap oxidises and expands making it impossible to remove the screw. I use a product called Tefgel on the screw and that has always worked for me.